A DESCRIPTION OF THE REQUEST :
When a cell's string contents are cut off because of the cell's size, it would be nice to have the option to show the entire contents with an in-place tool-tip like many UIs do. A good example of what I would like to see is this project: https://datatips.dev.java.net/

The datatips project has some problems with "unintentionally retained" memory (doesn't use weak references for its listeners) and different look and feels, but I think it is the best implementation of this idea that I've seen.

JUSTIFICATION :
UI parity with OSes. For example, this datatip behavior is part of Windows Explorer. Open up explorer (windows key + e). The folder tree down the left side has the datatip behavior. If a folder name is cut off then hovering with the mouse will display the entire name in a sort of tool tip.

There are several implementations of this idea for JTable/JList that I found out on the web, so there seems to be some demand for it.